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Title: Charge trapping of Ge-nanocrystals embedded in TaZrO{sub x} dielectric films

Ge-nanocrystals (NCs) were synthesized in amorphous TaZrO{sub x} by thermal annealing of co-sputtered Ge-TaZrO{sub x} layers. Formation of spherical shaped Ge-NCs with small variation of size, areal density, and depth distribution was confirmed by high-resolution transmission electron microscopy. The charge storage characteristics of the Ge-NCs were investigated by capacitance-voltage and constant-capacity measurements using metal-insulator-semiconductor structures. Samples with Ge-NCs exhibit a maximum memory window of 5 V by sweeping the bias voltage from −7 V to 7 V and back. Below this maximum, the width of the memory window can be controlled by the bias voltage. The fitted slope of the memory window versus bias voltage characteristics is very close to 1 for samples with one layer Ge-NCs. A second layer Ge-NCs does not result in a second flat stair in the memory window characteristics. Constant-capacity measurements indicate charge storage in trapping centers at the interfaces between the Ge-NCs and the surrounding materials (amorphous matrix/tunneling oxide). Charge loss occurs by thermal detrapping and subsequent band-to-band tunneling. Reference samples without Ge-NCs do not show any memory window.
Authors:
; ; ; ;  [1] ; ;  [2] ;  [3]
  1. Institute of Applied Physics, TU Bergakademie Freiberg, D-09596 Freiberg (Germany)
  2. Institute of Materials Science, TU Bergakademie Freiberg, D-09596 Freiberg (Germany)
  3. Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, D-01314 Dresden (Germany)
Publication Date:
OSTI Identifier:
22399129
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 2; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANNEALING; CAPACITANCE; CAPACITY; DIELECTRIC MATERIALS; ELECTRIC POTENTIAL; FILMS; GERMANIUM; INTERFACES; LAYERS; NANOSTRUCTURES; SEMICONDUCTOR MATERIALS; SPATIAL DISTRIBUTION; SPHERICAL CONFIGURATION; SPUTTERING; TANTALUM COMPOUNDS; TRANSMISSION ELECTRON MICROSCOPY; TRAPPING; TUNNEL EFFECT; ZIRCONIUM OXIDES